Stoker.



H. B. HOLT. s'roxna.

APPLICATION FILED DBO. 8, 1913.

Patented Dec. 22, 19 14;

4 SHEETS-SHEET 1.

INVENTOR H. B. HOLT,

STOKBR.

APPLICATION FILED DBO. 8, 1913.

Patented Dec. 22, 19M.

4: SHEETS-SHEET 2.

H. B. HOLT.

STOKER.

APPLICATION FILED DEG. 8, 1913.

Patented De0.22,19M

4: SHEETS-BHEET 3.

H..B. HOLT.

STOKER.

APPLIOATION FILED DEG. s, 1913.

Patented Dec. 22, 1914.

4 slums-$3231 4.

INVENTOIF! HARRIS B. HOLT, F DORMONT BOROUGH, PENNSYLVANIA, ASSIGNOR '10 ROSEDALE FOUNDRY & MACHINE COMPANY, OF PITTSBURGH, PENNSYLVANIA, A CORPORA- [DION or PENNSYLVANIA.

STOKER.

Patented Dec. 22, 1914.

Application filed December 8, 1913. Serial No. 805,318.

To all whom it may concern Be it known that I, HARRIS B. How, residing-at Dormont Borough, in the county of Allegheny and State of Pennsylvania, acitizen of the United States, have invented or d scovered certain new and useful Improvements in' Stoker's, of which improvements the following is a specification.

The invention described herein relates to coal stokers for furnaces, and has particu ous layer of predetermined constant thickness, and may be agitated during its travel without liability of varying the thickness of the layer.

While the invention may be used in itself as a complete stoker, it is illustrated herein as being supplementary to a chain grate stoker, and as such adapted to feed coal thereto in a semi-ignited and well brokenup condition, so that the coal may, thereafter, he completely ignited.

In the accompanying sheets of drawings, illustrating the invention, Figure 1 is a front view of one embodiment thereof shown in connection with a chain grate stoker,

various parts being broken away and others shown in section in order to better illustrate the construction; Figs. 2 and 3 are end elevations taken, respectively, on the right and left sides of Fig. 1; and Fig. 4- is a sectional view takenon the line IVIV, Fig. 1.

The general construction and arrangement of the illustrative embodiment of my invention is seen best in Fig. 4:. As shown therein, a coal hopper 1 extends along the upper partof the furnace, and is provided at its lower end with a discharge opening 2, which may be regulated by means of a vertically movable gate 3. A plurality of rotatablefeed or grate rolls {l are arranged in an incline extending downwardly from the discharge opening, their axes being parallel to each other, and the peripheries of adjacent rolls being substantially tangent. The uppermost roll is arranged beneath the lip of-the discharge opening 2, and, its surface being corrugated, drags. coal from the hopper and feeds it to the next successive roll, and so on until the coal drops from the lowermost roll to-the ghain grate 5. By this general arrangement it will ,be seen that the particles of coal, as they are moved in a continuous layer down the incline of rollers, are, at the points 'of tangency of adjacent roll surfaces, glven a reciprocatory movement with'relation to each other in a direction substantially normal to the general plane of rolls, thus effecting a breaking up of the mass otherw se having a tendency to cake together. However, in addition to the agitation thus produced, means are provided, in the form of reciprocating pokers 6, to further stir the coal as it is moved pver the rolls, and to serve as a means for preventing all, or large portions of, the layer of coal from sliding or 'avalanching down its inclined support, and

thus become unevenly distributed upon such support or upon a chain-grate leading from it. Such pokers preferably extending be tween the rolls at suitable longitudinal intervals thereof. The several operating parts extend between, and for the. most part are secured to, end frames 7 and 8, their coordination and driving means being fully explained hereinafter. An ignition arch 9 extendsover the rolls 4. and chain 5, the purpose of which is well understood and need not be explained herein.

Referring now with greater particularity to the details of construction, the hopper 1 may be of any desired form to the end that coal may be fed through a slot-shaped opening to the top roll 4:, that shown herein extending between the end frames 7 and 8, and discharging directly tosuch roll. The gate 3 may be properly adjusted by means of a hand-operated worm shaft 10 and a gear wheel 11, which carries a drum 12, to which the gate chain 13 is attached, such arrangement bein well'known by those skilled in the art. the chain grate 5 is also well known, the chain being continuous and extending over and between cog wheels 14 mounted on end shafts, one of which, 15, is illustrated herein. Suitable supporting rollers 16 are placed below the horizontal portions of the chain as shown. 7

Each feed or grate roll l preferably consists of a plurality of semi-cylindrical iron he construction and operation of 7 treme positions.

castings 17, mounted upon an angular shaft 18, as clearly shown in Fig. l. The locking of the roll parts or segments is effected by means of rods 19 which extend through suitable holes in the segments from end to end of the rolls. The segments 17 are arranged in pairs, each segment being laterally applicable to the shaft 18. Adjacent pairs meet in planes transverse to the shafts, as indicated by the lines 71, and the longitudi nal meeting planes of the segments forming adjacent pairs are disposed at right angles with respect to each other, thus effecting, through the rods 19, an interlocking of the segments.

As will be readily seen, the surfaces of the rolls are corrugated, except at the poker grooves 20, to drag the coal from the hopper and to prevent it from sliding over them. The pokers 6, which preferably operate in pairs through the grooves 20, are best seen in Fig. 4, wherein. they are shown in full lines in their intermediate position, and in dotted lines in their opposite ex- Each pair of pokers'is pivotally connected to the outer ends of an arm 21, which is secured at its center to a shaft 22, to which a rocking motion is imparted in a manner hereinafter described. In order to support the rolls 4, and thus divide the span between the end frames, suitable brackets are provided. One of such brackets is shown herein, at the center of the rolls, and is seen in'Figs. 1 and 4. This bracket consists of a casting 23, extending between and secured to an I-beam 24 and a T-section 25, and a second casting 26 secured to the opposite side of the section 25, the I-beam and T-section being connected .at their ends to the frames 7 and 8. The castings 23 and 26 are provided with suitable bearings for rollers 27, upon which the feed rolls 4 bear. It will thus be seen that the weight of the feed rolls 4, and of the coalcarried on them, is partly sustained otherwise than through the end bearings of such rolls.

The driving mechanisms for the several movable parts of the stoker comprise means for rotating each of the rolls 4 in a right handed or clock-wise direction as seen in Fig. 4, means for moving the chain grate 5 through the furnace, and means for reciprocating the pokers 6. Preferably the rotation of the rolls 4 and the movement of the chain 5 are coiirdinated in such manner that the peripheral speed of the rolls is the same as the speed of the chain; while the pokers are separately driven so that their range of reciprocation may be controlled independently of the speed of rolls and chain. The rolls and chain grate are, in this embodiment of the invention, driven by means of a pawl and ratchet mechanism. An eccentric 28, mounted on a rotatory line shaft 29, causes the arm 30 to reciprocate, which, through the bell-crank lever 31 and compressible arm 32, causes a pawl arm 33 to oscillate upon a shaft 34. The pawl 35 of the arm 33 engages a ratchet-wheel 36, which is rotatably mounted on the shaft 34 and a locking pawl 37 secured to the end frame 7 prevents the backward movement of the ratchet wheel. As will readily be seen the effective point of connection of the arms 32- and 33 may be adjusted radially with relation to the shaft 34, so that the extent of movement of the ratchet wheel 36 by each oscillation of the arm 33 may be varied as desired. The shaft 15, to which the chain-driving cog wheels 14 are secured, is driven by the ratchet wheel 36 through pinion 38, rotatably mounted on shaft 34 and secured to the ratchet wheel, and pinions 39, 40 and 41, such driving mechanism being clearly seen in Figs. 1 and 2. Each roll 4 is provided at its left end as seen in Fig. 1, with a pinion 42, and such pinions are driven by the shaft 15 through a chain cog 43 keyed to said shaft, chain 44, chain cog 45 rotatably mounted in the end frame 8, pinion 46 secured to cog wheel 45, and pinions 47 and 48 also rotatably mounted in said frame and which mesh with the pinions 42 and 46 as shown.

In operation, the ratchet wheel 36 and the pinion 38 secured to it are driven in a right hand direction, as seen in Fig. 2. The pinion 38 drives the pinon 39 and pinion 40 secured thereto in a left-hand direction, the pinion 4O driving the pinion 41, and hence the shaft 15 and chain cogs 14, in a right hand direction to move the chain grate through the -fire box. As viewed in Fig. 3,

the shaft 15 moves in a left hand direction,.

whereby the cog wheel 45 is driven.in a left-hand direction, carrying with 1t the pinion 46 which meshes with the pinions 47 and 48 causing them to rotate in a right hand direction. The pinions 47 and 48 in turn mesh with the pinions 42 and cause them to revolve in a left-hand direction.

As stated heretofore, the pokers 6 are preferably operatedindependently of the rolls 4. However, the mechanism shown hereinfor effecting such operation is similar to that used in driving the rolls. A second pawl arm 49 is rotatably mounted on the shaft 34 and is oscillated through an eccentric 51 mounted on the line shaft 29, arm .52, bell-crank lever 53, and compressible arm 54. A ratchet wheel 55 is keyed to the shaft 34,- a pawl 56 being secured to the arm 49 to move such wheel, and a pawl 57 to the frame 8 to lock the wheel against backward movement. The shaft 34 extends the full width of 'the machine and is rotatably mounted in the end frames 7 and 8. At the right end of such shaft a pinion 58 is keyed and meshes with a pinion 59, to which one 'in opposite directions, of the oker shaft 2-2,

thus causing the pokers to reciprocate between the rolls 4. The rapidity of movement of the pokers may, as in the case of the roll-driving mechanism, be controlled by adjusting the effective point of connection be tween the arms 54: and 49.

In the operation of the improved stoker, when used to feed coal well broken upfland partly ignited to a chain grate, coal from a hopper 1 is dragged through the discharge opening 2 by means of the upper roll 4 and is carried over the successive rolls, being finally deposited upon the chain grate 5. The thickness of the layer thus carried overthe rolls may be varied by the gateB in the usual manner. However, for a given adjustment of the gate, the thickness of the layer will remain constant, that is to say, the action of the rolls and pokers will not cause the coal to slide or otherwise move unevenly. hen being moved over the rolls, the coal is agitated both by the action of the rolls and by pokers 6 which reciprocate between them. The trains of driving mechanisms for the rolls 4 and grate 5, and for the pokers 6 have been fully described and need not be now repeated. Bv providing separate chains of mechanisms, the rapidity of the action of the pokers may be varied with relation to the movement of,the feed rolls. Also, by constructing the rolls 4 of separately removable segments, such segments as may be destroyed by the heat of the furnace may be replaced without removing the entire roll.

I claim as my invention:

1. In a coal stoker, the combination of a furnace chamber, a chain grate therein, a hopper having a discharge opening, means for feeding in an inclined plane and exposed to the heat within the chamber a layer of coal from the hopper to the grate, and intermittently operating means for preventing an uneven sliding of the layer of coal thus fed.

2. In a coal stoker for furnaces, the combination with a supply hopper having a discharge opening, of a plurality of feed rolls arranged parallel and adjacent to each other in an incline leading from said hopper opening, means for rotating said rolls to convey coal from said hopper and in a continuous sheet in a furnace chamber, a plurality of pokers extending between adjacent rolls, and means coordinated with said roll-rotating means for reciprocating said pokers in a direction transverse to the general plane of the rolls.

3. In a coal stoker for furnaces, the combination with a supply hopper having a discharge opening, of a plurality of feed rolls arranged parallel and adjacent to each other in an incline leading from said hopper opening, means for rotating said rolls to convey coal from said hopper and in a continuous sheet in a furnace chamber, a rocking shaft below and parallel with the axes of said rolls, a plurality of arms secured to said shaft, poking bars pivoted to said arms and extending between adjacent rolls, and means coordinated with said roll-rotating means for rocking said shaft.

4. In a coal stoker for furnaces, the combination with a supply hopper'having a discharge opening, of a plurality'of feed rolls arranged parallel and adj acent to each other in an incline leading from said hopper opening, means for rotating said rolls to convey coal from said hopper and in a continuous sheet in a furnace chamber, a rocking shaft below and parallel with the axes of said rolls, a plurality of arms secured to said shaft, poking bars pivoted to said arms and extending between adjacent rolls, means coordinated with said roll-rotating means for rocking said shaft, and means for varying the extent of reciprocation of the pokers.

In testimony whereof I have hereunto set my hand.

HARRIS B. HOLT. Witnesses:

PAUL N. CRI'roHLow, FRANCES J. TOMASSON. 

